This invention relates to photography, and particularly to recording of digital images.
In the field of photography, photographers have a choice between cameras that record and store analog images on conventional photo-sensitive film, and digital cameras that record and store digital image files using digital transducers such as charge coupled devices (CCD). Each type of camera has its advantages and disadvantages.
Digital cameras save money by not requiring expenditures on film or processing. Also, recorded digital images are available instantly for viewing, and may be transmitted as electronic signal data to remote locations for instantaneous use and viewing. Digital images are readily archived in compact media that requires only minimal physical space, and may be indexed with associated data files that make image retrieval practical, even from an archive containing an extensive multitude of stored image files. Stored data files preserve image qualities without gradual degradation over time, as occurs with chemically based conventional film and prints.
Digital cameras have certain limitations compared to conventional analog film-using cameras. Primarily, the images recorded by film-based cameras have much greater resolution, and capture far more image detail. While digital cameras have resolutions yielding detail on the order of one to several million pixels, conventional fine grain film and good quality lenses are capable of 10 to 100 times greater detail. Larger film formats are capable of recording an additional order of magnitude of detail. Another advantage of conventional film images is that a physical piece of film carrying an image is difficult to alter, while digital image files are readily altered, without discernible traces of tampering. Where security is important, a physical film image may be stored to preserve a chain of custody, which may be important for recorded images of legal evidentiary significance.
For some applications, both digital and analog cameras are used redundantly to provide the benefits of each. For law enforcement evidence gathering, such as at a crime scene, a photographer may record each scene twice, once with each type of camera. This provides a readily stored, indexed, and recalled electronic image, and avoids the cost of processing film, until and unless a recorded image becomes critical, such as where the fine detail or tamper resistance of an analog film image is needed. However, such practices are cumbersome, and require careful cross-indexing between stored digital and analog images. In addition, a photographer may not precisely frame images that are supposed to be the same, so that the direction, focus, and exposure are different. Further, images with different camera types are taken sequentially, so that there may be temporal changes in the scene being recorded during the interval.
The present invention overcomes the limitations of the prior art by providing a camera having both a digital image transducer and an analog film transport mechanism operable to advance film across a film focal plane. An imaging system generates an image on the image transducer, and generates an image on the film focal plane. A triggering system may operate to generate the images simultaneously, and the imaging system may include separate lenses having optical properties selected to generate images of essentially the same scene.